<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    .box{
        width: 100px;
        height: 100px;
        background: red;
    }
    @media (max-width:768px){
        .box{
            background: green;
        }
    }
    @media (min-width:768px) and (max-width:1100px){
        .box{
            background: yellow;
        }
    }
    </style>
</head>
<body>
    <!-- 根据设备尺寸不同给用户呈现不同的界面 -->
    <div class="box">

    </div>
</body>
</html>